With reference to FIGS. 1 and 2 hereof, kinetic energy (KE) projectiles (100) may be used to defeat light and heavy vehicle armor. KE projectiles (100), include a KE penetrator rod (102) which is threaded to a front nose (101) and a fin (103) in the rear. A sabot (104) is attached to the penetrator rod (102) by the pressure flanks or thread like buttress grooves (105). There may be 2 or 3 sabot petals (104). The penetrator rod (102) may be placed against each sabot buttress groove 105, (see FIG. 2, holding the sabot (104) tightly against the rod (102). A breakaway snap ring may be added to the front and rear of the sabots to hold the assembly together. The KE projectile (100) can be attached to a cartridge case containing propellant (not shown), (101+102+103) by a snap joint (106) or other mechanism at the rear of the saddle. Upon gun launch the snap rings would break and allow the sabot parts (104) to move away from the in-flight KE projectile (101+102+103) and impact the ground a short distance from the gun. The in-flight KE projectile (101+102+103) continues on to the target and defeats the target by rapid penetration (kinetic energy) through the armor, e.g. The interface between the KE rod (102) buttress grooves (105) and the matching sabot buttress grooves (105) is important during the period the projectile travels down the bore of the gun. The buttress grooves carry the mass of the KE rod (102) and nose (101) and if not properly designed, the projectile would shear during launch and result in overall structural failure of the projectile. It can be seen that a substantial quantity of matching buttress grooves (105) are used to support the sabot(s) (104), KE rod (102) and nose (101). The numerous number of grooves (105) are needed to ensure an even distribution of projectile load forces over the buttress grooves. Moreover, the sabot (104) shown, which is desired to now be made of lightweight composite (carbon fibers in epoxy matrix), conventionally was made of aluminum. The replacement of aluminum sabots with composites would result in significant parasitic weight reduction, which in turn result in higher velocities of the projectile for a given propelling charge, and ultimately greater lethality on a target. The composite sabots as to be designed here are stronger than their aluminum counterparts particularly in tensile load carrying sections of the sabot, but have a lower shear carrying capability therefore resulting in relatively weaker buttress grooves. The problem of poor shear carrying capability in the buttress grooves gets worse when the projectile being designed is of very small calibers (e.g., sniper ammunition size), because the groove sizes start to approach the sizes of the fibers being used in the composite sabot. Also, the conventional groove design, when scaled down possesses very sharp features, which exacerbate the problem by creating stress concentrations in the composite sabot grooves.
On some KE projectiles, a tipping ring is needed to allow the sabots to move outward as the sabots peel off the projectile, so that the sabots do not strike the fin when they are discarded. The tipping ring is usually at the end of the buttress grooves at the fin end, and is usually larger than the buttress grooves. It is another component that adds weight and financial cost to the overall projectile.
In order for the in-flight KE projectile (101+102+103) to be launched properly as a small caliber, e.g, fly well, and defeat the target, several features need to be accomplished. They are as follows:
1) The sabots (104)/rod (102) interface needs enough buttress grooves to support the penetrator during launch.
2) The buttress grooves (105) should be small enough in order to keep the drag of the projectile low enough to ensure high striking velocity on target.
3) A tipping ring may need to be added to ensure proper sabot discard after the projectile exits the muzzle of the gun.
4) The desired location of the center of gravity should be made usually toward the front of the projectile to enhance its flight stability which in turn helps improve its accuracy.
What is needed is a new way to attach the sabots to a small penetrator, particularly when opting to use a composite sabot, to reduce costs, reduce the number of complex features like buttress grooves, to maintain clean sabot discard, and to improve the stability of the flight projectile by moving the center of gravity forward. This invention solves all these problems.